FR2997590A1 - Method for communicating visible light data on mobile terminals by organic type electronic device, involves utilizing module comprising photosensitive receiver to generate output signal in response to reception of light signal - Google Patents

Abstract

The method involves utilizing a first module (2) comprising a visible light transmitting component (2a) to switch a response to switching set point in a controlled manner for generating a light signal. A second module (3) e.g. plug-in module, comprising a photosensitive receiver (3a) sensitive to the light signal emitted by the transmitting component is used, where the receiving component is adapted to generate an output signal in response to the reception of the light signal. The light transmitting component and the photosensitive component are partially made of organic materials.

Description

The invention relates to communication by visible light (CLV) using electronic devices of organic type. BACKGROUND OF THE INVENTION The worldwide traffic of Internet data on mobile terminals continues to increase and at the end of 2010, nearly 14 million mobile terminals (all types) were connected to the Internet network in the world and consumed overall 242 petabytes per month.

This figure is expected to grow to 788 million mobile Internet users with consumption reaching 6.3 exabytes per month. The freedom offered by wireless technologies is based on the availability of frequency resources, whose scope is physically limited. Demand growth therefore confronts the regulator of this resource with a situation of scarcity that must be taken into account when setting the technical and economic conditions for access to the radio spectrum. The few probes lorées to solve this problem currently rely on greater flexibility in the use of frequency bands and on the hypothesis of the release of the few bands used by technologies that are destined to disappear as has been the case. VHF-UHF and as will probably be GSM. The strong development of wireless communication technologies (Wifi, Bluetooth, 3G, Zigbee, DECT ...) has generated a new source of pollution called electromagnetic pollution. The term pollution is used because some electromagnetic fields are suspected, for living species, to be a disturbance factor, to affect their health or reproduction. In May 2011, WHO classified "potentially carcinogenic" microwave radiation and recognized Electromagnetic Hypersensitivity or HSEM as a Disability.

The so-called CLV technology for Visible Light Communication (or VLC for Visible Light Communication, or LiFi for Light Fidelity), is an emerging technology in which LED-based ambient lighting is used not only for its primary function but also for also to transmit in free space data streams at very high speed. The lack of a license to operate, given the free use of optical frequencies, is an important factor from an economic point of view. In addition, while the health effects of microwave technologies are provoking more and more debate, light is emerging as a natural component of our environment. The CLV technology is based on the switching of high-frequency LEDs (semiconductors) to reach the record known to date of 800 Mbps. The CLV technology is based on a two-module device, a transmitter capable of switching lighting and a receiver capable of detecting these switches.

Currently, CLV technology preferably uses so-called inorganic electronic components, such as silicon for photodiodes, gallium nitride for LEDs and phosphorescent compounds for white LEDs.

OBJECT OF THE INVENTION An object of the invention is to propose a new mode of implementation of communication by visible light, more easily used and integrable in the environment.

SUMMARY OF THE INVENTION In view of achieving this object, a method of communication by visible light is proposed, comprising the use of a first module comprising at least one visible light emitting component capable of switching in a controlled manner in response. to a switching setpoint for generating a light signal, and a second module comprising at least one receiver component responsive to the light signal emitted by the transmitter and adapted to generate an output signal in response to the reception of the light signal in which, according to the invention, the light-emitting component and the photosensitive component are at least partly made of organic materials. By organic materials is meant herein the carbon-based materials useful for making light-emitting and photoreceptor components, as opposed to inorganic materials such as silicon. Organic / printed electronics offer two major advantages over "traditional" electronic applications made from silicon or other conventional mineral components: - it allows the design of devices on flexible substrates and thus offers a broad spectrum of new applications, given the flexibility of supports and surfaces made using this technology; - It allows the realization of electronic applications through manufacturing techniques whose investments and costs are infinitely lower than in the silicon industry. Almost all these products will be foldable and laminar elements that will print using the same process or similar processes and above all highly recyclable. The advantages of organic electronics are numerous: low production costs, better recyclability, extension to large active surfaces but also to flexible surfaces. The invention therefore makes use of the advantages of this technology to enable the implementation of CLV using light-emitting components and organic photoreceptors. Preferably, the production of these components makes use either of successive sublimation methods for small molecules or of so-called printing methods, in thin films, for molecules of high molecular weight, such as polymers (spin- coating, ink-jet, etc.). The process of the invention is preferably carried out by means of the following organic components: light-emitting components based on light-emitting diodes of the OLED (organic light-emitting diode) or PLED (light-emitting polymer) type; photoreceptor components comprising organic photovoltaic cells; organic transistors; all preferably mounted on flexible and flexible circuit boards. In the context of the invention, photodetector components combining organic light emitting diodes and organic thin film transistors (called OTFTs for organic thin film transistor) can of course be used. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood in the light of the following description of particular embodiments of the invention, with reference to the figures of the accompanying drawings, in which: FIG. 1 is a block diagram illustrating the principle of operation of a CLV communication by means of two modules according to the invention; FIGS. 2A and 2B are schematic diagrams of the two modules of the device of FIG. 1, based on organic materials according to the invention; FIGS. 3A, 4A and 5A are schematic top views of three organic electronic devices that can equip the module of FIG. 2A and including organic emitting components and organic receiving components according to alternative embodiments of the invention. invention; FIGS. 3B, 4B and 5B are respective sectional schematic views of the three organic electronic devices of FIGS. 3A, 4A, 5A; FIG. 6A is a schematic view from above of an electronic device that can equip the module of FIG. 2B; - Figure 6B is a schematic sectional view of the electronic device of Figure 6A.

DETAILED DESCRIPTION OF THE INVENTION The CLV devices of the invention consist of two distinct modules whose characteristics may vary according to the applications. In a first embodiment of the invention, the transmitter module comprises an emitter component of the OLED or PLED type associated with a thermoelectric material and a transistor (organic or not), whereas the receiver component comprises a PVO cell or a organic photodiode. These components may be used in a one-way visual broadcast mode (or broadcast in English). In a second embodiment of the invention, each module includes both a transmitter for transmitting a light signal to another device, and a receiver for receiving a light signal from another module. Such a module may be integrated into a computer-type apparatus, preferably a television screen. Preferably, such a module is equipped with an electronic device which comprises, according to the invention, a card or other medium containing both one or more transmitter components integrating OLED or PLED type diodes and one or more receiver components incorporating PVO or organic photodiode cells to receive the data to be returned. Preferably, the device also comprises one or more layers of thermoelectric material, and, where appropriate, one or more transistors (organic or otherwise). These modules are adapted to the implementation of a two-way visual diffusion mode. Receiver modules that are associated with infrared transmission means may also be provided according to the invention. Thus, such a so-called mixed module preferably comprises an electronic device comprising one or more receiver components integrating PVO type cells or organic photodiodes, and an infrared emitter component incorporating one or more infrared diodes for the return of data. In the same way, the device comprises layers of thermoelectric material and, if necessary, one or more transistors (organic or not). These modules are adapted to the implementation of a mixed bidirectional broadcast mode, namely visual reception and infrared transmission. Figure 1 shows the operating principle of a CLV device. A source 1, for example an ethernet port, an SD card, micro-SD, a female USB port, a camera, an audio source, an internet source, a video source or all sources sending data signal (s) is associated with a first module 2 comprising a transmitter component 2a adapted to transform the data signals from the source into a modulated light signal. A second module 3 (for example a plug-in module, in English dongle) is provided with a photorespector 3a which perceives the modulated light signal to decode it and send it here to a male USB module 4. In the case of bidirectional communication, the first module 2 will also include a photoreceptor component 2b adapted to receive modulated light signals coming from a transmitter component 3b equipping the second module 3. As can be seen in FIG. 2A, the first module 2 comprises a microcontroller 5, for example PIC or FPGA type. The microcontroller 5 sends data frames 6 to a transistor 7 which may be conventional or of organic type. The role of transistor 7 is to modulate the data frames according to here an OOK type modulation (for on-off keying). The modulated signal is sent to an electronic device 100 including transmitter component 2a for light emission modulation. In the case of a bidirectional communication, the electronic device 100 includes the 2b receiver component photosensitive to a light signal modulated according to a modulation 00K. This receiving component generates a signal which will be sent to a device 8 for filtering, amplifying and digitizing. The signal thus processed is sent to the microcontroller, to be transmitted to the outside. Thus, the electronic device 100 includes the components 2a and 2b of FIG.

As can be seen in FIG. 2B, the second module 3 has an architecture very close to that of the first module 2. It comprises a mixed electronic device 200 for receiving the optical modulation and, if necessary, for emitting in the infrared.

Here, the electronic device 200 includes the component 3a of Figure 1 and, as will be detailed below, an infrared emitter component. We also find a device 8 filtering, amplification and digitization, a microcontroller 5, and a transistor 7.

Organic electronic devices 100 are now described in more detail. Three different types of organic electronic devices, denoted respectively 100a, 100b and 100c, in FIGS. 3, 4 and 5, are here described.

The electronic devices 100a, 100b, 100c are built on the same architecture. They comprise organic emitting components 101a, 101b, 101c and organic photoreceptor components 102a, 102b, 102c which are encapsulated in a transparent light-sensitive protective cover 10a, 10b, 10c. The components are fixed on a support 111a, 111b, 111c adapted to dissipate heat. The support 111a, 111b, 111c is itself attached to a substrate 112a, 112b, 112c of thermoelectric material. The assembly is welded to a layer 113a, 113b, 113c of thermally conductive material. The whole is reported on a printed circuit board 114a, 114b, 114c. The transmitting components 101a, 101b, 101c are here all of similar structure and vary only by their shapes and surfaces. They each comprise a protective cover 23a, 23b, 23c which covers a diode 22a, 22b, 22c of the OLED or PLED type, the latter being associated with a substrate 21a, 21b, 21c of thermoelectric material (for example an alloy of tellurium and bismuth) which provides the interface with the diode, itself associated with a layer 20a, 20b, 20c of thermally conductive material (for example copper). Each transmitting component is attached to the support 111a, 111b, 111c of the associated device. According to a particular aspect of the invention, the thermoelectric material substrate is made of organic material, for example based on n-type or p-type semiconductor polymer. Preferably, the organic light-emitting diodes that can be used in the context of the invention are of two types, either based on more or less complex organic molecules arranged in multilayers (OLEDs) or on the basis of polymers (PLEDs) to reduce the number of layers. . OLEDs are formed by the juxtaposition of several organic layers fulfilling the roles of hole drivers, emissive layers and electronic conductors successively. These multilayers can be supplemented with hole or electron blockers. Generally, these different layers are deposited by controlled sublimations. All these layers are between the two electrodes, cathodes and anodes.

PLEDs are light-emitting diodes in which the n-type and / or p-type semiconductor layers consist wholly or partly of high molecular weight molecules such as oligomers or polymers. The PLEDs can also be in the form of a single monolayer consisting of a p-type semiconductor polymer block, an n-type block and phosphorescent dopants more or less linked to the monolayer. In the case of PLEDs, the monolayer (s) can be deposited on different types of substrates, glass, quartz, polymers, silicone etc. In all cases, these different light-emitting diodes can emit in all the visible range and even in the near infra-red and also emit white light at different heats. This control of the emission length is done by varying the nature of the phosphorescent dopants as a function of the fluorescence of the various semiconductor layers and the energy gaps of these different layers. Currently, OLEDs are the most commercially advanced ones with the highest performance in lm / w or Cd.A-1. The photoreceptor components 102 are made in a similar manner. They comprise a layer of thermally conductive material 30a, 30b, 30c on which is deposited a thermoelectric material substrate 31a, 31b, 31c which interfaces with a PVO cell or an organic photodiode, 32a, 32b, 32c, and which forms the photosensitive detector itself. A filter layer 33a, 33b, 33c is hereby reported on the assembly to allow only adequate wavelengths to arrive on the photosensitive detector. The whole is covered by a protective cover 34a, 34b, 34c transparent to visible light. The organic photovoltaic cells, or PVOs (in English OPV for organic photovoltaic) absorb photons to generate excitons which will be separated into charge carriers collected at the electrodes, inducing the creation of an electric current representative of the received light signal. As a result, the PVO cells consist of two main layers, one with a high electronic end and high ionization potential, such as the electron acceptor layer and the layer as the electron donor. Nevertheless and as before, the PVO cells can be made either by small molecules or by polymers, making sure to absorb the maximum wavelength in the visibil- ity. There are three main types of structure of a PVO cell: - either two donor-acceptor layers in planar heterojunction between the two electrodes, - either in volume heterojunction (the two layers are mixed), - or in blocked voluminal heterojunction between two acceptor and donor films. Blocking layers may also be inserted between the electrodes and the active layer (s). In parallel with these totally organic cells, there are also so-called "hybrid" cells, which also make it possible to produce cells of large areas. These "hybrid" cells are also called nanocrystalline dye cells, called Gratzel cells. In this context, the active layer is formed on the one hand of nanoparticles of titanium oxide, as semiconductor, covered with a dye, most often ruthenium (II) -based coordination complexes and on the other hand side of the active layer, an electrolytic solution largely comprising the electrochemical couple 1113- which also allows the transfer of electrons between the TiO2 photoelectrodes and the counter-electrode. Organic photodiodes are conceptually close to OPVs cells by the generation of a photocurrent. They can be formed by multilayers based on small molecules or by the use of semiconductor polymers. The nature of the components remains close and the principles of operation are similar to the OPVs cells. Only the nature of the chemical components can vary depending on the applications targeted, in particular if it is desired to have organic photodiodes sensitive to near-infrared rays while being transparent in the visible.

The three electronic devices 100a, 100b, 100c are distinguished only by the relative arrangement of the transmitter components 101a, 101b, 101c and the receiver components 102a, 102b, 102c. Thus, the device 100a comprises a central organic receptor component 101a encircled by a number of organic emitter components 102a. The device 100b presents a tiling of transmitting components 101b and receiving components 102b. Finally, the device 101c comprises a rectangular organic emitter component 101c occupying an appreciable surface of the device, framed on two of its sides by two organic photoreceptor components 102c. Of course, these configurations are given as an indication, and we can of course have the components in any suitable configuration. In particular, it will be possible to invert the positions of the transmitting components and the receiving components. Concerning the mixed electronic device 200 of the second module 3, it comprises as the electronic device 100 a support 211 adapted to dissipate the heat and on which the components are fixed. The support 211 is itself attached to a substrate 212 of thermoelectric material. The assembly is welded to a layer 213 of thermally conductive material. The whole is reported on a printed circuit board 214.

On the support 211 are reported here a photoreceptor component 102 of the same constitution as that already described, as well as an infrared emitter component 103. Here, the receiver component 102 covers almost the entire surface of the device 200. two components are covered with a common cover 215 which, however, exceeds a protective cover 45 forming a diffusion lens of the infrared emitter component 103. The infrared emitter component 103 comprises, in addition to the protective cover 45, a heat-conducting support 40, on which a layer of thermoelectric material 41 is deposited. The diode portion itself comprises a thermally conductive support 42 on which a layer of organic material 43. The organic layer is also either hybrid, or multilayer or monolayer and between two electrodes. The whole is covered 44 serves as a UV-visible filter. Thus, the infrared emitter component is very similar to the emitter component in the visible, except that the organic layer is adapted to emit in the infrared. Thanks to the provisions of the invention, optical visual communication is made possible by the use of electronic components with organic materials.

Preferably, the organic materials are supported by sublimation, printing, or any other suitable method. The inorganic layers are preferably made by metallization The invention is not limited to what has just been described, but on the contrary covers any variant within the scope defined by the claims. In particular, those skilled in the art will have understood that the electronic devices fitted to the modules may comprise, as desired: - only one or more organic emitter components, - only one or more organic receptor components, - a combination of emitter components and organic receptor components; all of which may include other organic components, such as transistors. The electronic devices may further include transmitters or receivers in other wavelengths, such as in the infrared as shown, whose transmitting component may be made using similar organic technology. , or in other wavelengths, such as WiFi, radio_ The protective covers may be made by depositing a glue or protective varnish transparent to visible light.

Claims (9)

REVENDICATIONS1. A visible light communication method, comprising the use of a first module (2) comprising at least one visible light emitting component (2a, 101) capable of controllably switching in response to a switching command to generate a light signal, and a second module (3) comprising at least one receiver component (3a, 102) responsive to the light signal emitted by the transmitter and adapted to generate an output signal in response to the reception of the signal characterized in that the light emitting component and the photosensitive component are at least partially made of organic materials. 2. Method according to claim 1, wherein at least one of the modules of an electronic device carrying the transmitting component and / or the receiving component is equipped, the device comprising: a support (111; 211) adapted to dissipate; the heat, and on which the component (s) are reported; a substrate (112; 212) of thermoelectric material, a layer of thermally conductive material; a layer (113; 213) of thermally conductive material; - a printed circuit board (114; 214). 3. The method of claim 2, wherein the emitter component comprises successively: a layer (20) of thermally conductive material; a substrate (21) made of thermoelectric material; an electroluminescent diode (22) based on organic material; - all protected by a hood (23); 4. The method of claim 3 wherein the light emitting diode is OLED or PLED type. 5. Method according to claim 2, in whichthe receiver component comprises: a layer (30) of thermally conductive material; a substrate (31) made of thermoelectric material; a photosensitive cell PVO (32) or an organic photodiode; - a filter layer (33) - all protected by a hood (34). 6. The method of claim 2, wherein the electronic device further comprises other organic components, such as an organic transistor. The method of claim 5 wherein the transistor is of the organic thin film type. 8. The method of claim 2 wherein the electronic device further comprises a transmitter component (103) in the infrared. 9. The method of claim 2 wherein the electronic device comprises both one or more emitter components (101) and one or more receiver components (102) which are arranged on the surface of the support in one of the following configurations: a receiving component is surrounded by transmitting components; a transmitting component is surrounded by receiving components; the transmitting components and the receiving components are arranged according to a tiling; a transmitting component is framed on two of its sides by two receiving components; a receiving component is framed on two of its sides by two transmitting components.